Our main objective is to exploit the ability of intensity correlation spectroscopy to measure the size distribution parameters of macromolecules under equilibrium conditions in solution to learn important new facts about the behavior of low and very low density lipoproteins (LDL and VLDL). This overall objective will be pursued by working toward three major goals. The first is to discover in what ways the size distributions differ among carefully chosen members of families having classical familial Types II and IV hyperlipoproteinemias, normals in the genral population, and normal members of the hyperlipemic families. The second goal is to study the effect of structural modifications on the conformation and configuration of LDL in solution by discovering their influence on LDL size and thereby gain insight into the structural importance of the modified elements. Finally, we intend to investigate the effect of various apo-LDL solubilization methods on its apparent size, degree of polydispersity and molecular weight.